US will 'suffer greatest pain' over sanctions - N Korea

North Korea has said the US will "suffer the greatest pain" over its role in the imposition of the latest sanctions on the country.

His comments come after the UN Security Council unanimously adopted a US-draft resolution slapping new sanctions on North Korea.

"The forthcoming measures ... will make the US suffer the greatest pain it ever experienced in its history," Han Tae Song, North Korea's ambassador to the UN, said on Tuesday.

The resolution is a water-down version of the original US proposal, but it does ban North Korea from importing all natural-gas liquids and condensates, as well as bans all textile exports and prohibits all countries from authorising new work permits for North Korean workers.

Han rejected the resolution as "illegal and unlawful" and said the US was "fired up for political, economic, and military confrontation".

North Korea is "ready to use a form of ultimate means", Han said.

On Wednesday, North Korea also called the sanctions a "heinous provocation aimed at depriving the DPRK of its legitimate right for self-defence and completely suffocating its state and people through full-scale economic blockade," according to a statement from the state-run Korean Central News Agency (KCNA).

DPRK stands for North Korea's formal name, the Democratic People's Republic of Korea.

The statement also said that the sanctions "verify that the road [North Korea] chose to go down was absolutely right and to strengthen its resolve to follow this road at a faster pace without the slightest diversion until this right to finish is over".

Monday's text is the ninth resolution unanimously adopted by the 15-member council since 2006 over North Korea's ballistic missile and nuclear programme.

It came in response to Pyongyang's sixth and largest nuclear test on September 3, which it said was of an advanced hydrogen bomb.

'Very small step'

For his part, US President Donald Trump said on Tuesday the latest UN sanctions on North Korea were only a very small step and nothing compared to what would have to happen to deal with the country's nuclear programme.

"We think it's just another very small step, not a big deal," Trump said at the start of a meeting with Malaysian Prime Minister Najib Razak.

"I don't know if it has any impact, but certainly it was nice to get a 15-to-nothing vote, but those sanctions are nothing compared to what ultimately will have to happen."

Trump has pledged not to allow North Korea to develop a nuclear missile capable of hitting the US.

The initial US proposal included an assets freeze on North Korean leader Kim Jong-un and a complete ban on countries selling oil to his government, but the measures were softened to appease China and Russia.

Steven Mnuchin, US treasury secretary, gave warning to China that if it did not follow through on the new sanctions, the US would "put additional sanctions on them and prevent them from accessing the US and international dollar system".